A new boron-doped gas microdosimeter for clinical Boron Neutron Capture Therapy

The Next Generation EU project ANTHEM (AdvaNced Technologies for Human-centrEd Medicine) aims at building a new accelerator-based BNCT facility in Caserta, Italy. In this framework, a new miniaturized Tissue-Equivalent Proportional Counter (mini-TEPC) with boron-doped cathode walls was designed and constructed, specifically developed to be used in BNCT clinical centres. The size of its sensitive cavity is only 1 mm to cope with the high intensity of BNCT neutron fields. The new detector was tested in reference fields where the thermal neutron component is negligible (photons, protons and fast neutrons), showing the same response as another mini-TEPC with identical design but for the boron doping. First tests were then performed at the thermal neutron column of the research reactor of the Laboratory for Applied Nuclear Energy in Pavia, Italy, with both detectors. Measured microdosimetric spectra were consistent with previous data taken at other thermal neutron sources. This paper presents the design of the new mini-TEPC and discusses the results of these first tests.